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Modbus Communications

7828 Density Transmitter Technical Manual

D-16

78285000_AA

D.7.2 EXAMPLE 2: READING LINE DENSITY (32-BIT REGISTER SIZE)

The 7828 is assumed to have been configured with Register Size = 32-bit (Register 48 =
FFFF

), and has slave address = 1

The following string will read the line density, which is held in Register 257 (0101

)

01 03 01 01 00 01 D4 36

The reply from the 7828 will be the same as for Example 1.

Slave address
(hex)

Command number: 3
(Read Register)

Number of
registers to read
Hi byte

Number of
registers to read
Lo byte

Checksum

(Automatically
inserted if you are
using ADView.)

Содержание 7828

Страница 1: ...Precision measurement solutions 7828 Density Transmitter TECHNICAL MANUAL 78285000 ...

Страница 2: ...this document may therefore be changed without notice To the best of our knowledge the information contained in this document is accurate and Solartron Mobrey cannot be held responsible for any errors omissions or other misinformation contained herein No part of this document may be photocopied or reproduced without the prior written consent of Solartron Mobrey ...

Страница 3: ...rials of construction DO NOT operate the 7828 above its rated pressure DO NOT pressure test beyond the specified Test pressure ENSURE all explosion proof requirements are applied ENSURE transmitter and associated pipework are pressure tested to 1 times the maximum operating pressure after installation ALWAYS store and transport the 7828 in its original packaging ...

Страница 4: ...7828 Density Transmitter Technical Manual iv 78285000_AB ...

Страница 5: ... 3 2 2 1 Boundary effects 2 3 2 2 2 Viscosity effects 2 6 2 3 STANDARD INSTALLATIONS 2 7 2 3 1 7828 orientation 2 8 2 3 2 Free stream installation flanged fitting 2 9 2 3 3 Free stream installation weldolet 2 10 2 3 4 T piece installation 2 11 2 3 5 T piece weldolet installation 2 12 2 3 6 Flow through chamber installation 2 13 2 4 INSTALLATION IN THE PIPELINE OR SYSTEM 2 14 2 4 1 Fluid at the sen...

Страница 6: ...ower 3 7 3 4 2 RS485 3 7 3 4 3 RS485 to RS232 3 8 3 4 4 RS485 Multidrop 3 11 3 4 5 Transmission mode 3 11 3 4 6 Analog 4 20mA output 3 11 3 5 INSTALLATION IN EXPLOSIVE AREAS 3 12 SECTION 4 USING ADVIEW 4 1 WHAT IS ADVIEW 4 1 4 2 INSTALLING ADVIEW 4 1 4 3 STARTING ADVIEW 4 2 4 3 1 Setting up serial communications 4 2 4 4 USING ADVIEW 4 5 4 4 1 ADView facilities 4 5 4 4 2 Menu bar 4 6 4 4 3 Configur...

Страница 7: ... check 5 4 5 3 2 On line calibration adjustment 5 4 SECTION 6 MAINTENANCE 6 1 GENERAL 6 1 6 2 GENERAL MAINTENANCE 6 2 6 2 1 Physical checks 6 2 6 2 2 Electrical checks 6 2 6 2 3 Calibration check 6 2 6 3 FAULT ANALYSIS AND REMEDIAL ACTION 6 3 6 3 1 Mechanical servicing 6 3 6 3 2 Time Period Trap 6 3 APPENDIX A SPECIFICATION A 1 GENERAL A 1 A 2 SPECIFICATION A 1 A 2 1 Sensor performance A 1 A 2 2 E...

Страница 8: ...DBUS COMMUNICATIONS D 1 INTRODUCTION D 1 D 2 ACCESSING MODBUS REGISTERS D 2 D 2 1 Establishing Modbus Communications D 2 D 3 MODBUS IMPLEMENTATION D 3 D 3 1 Register size and content D 3 D 4 MODBUS REGISTER ASSIGNMENTS D 4 D 5 INDEX CODES D 7 D 5 1 API product type D 7 D 5 2 Pressure temperature density and other units D 7 D 5 3 Special function D 8 D 5 4 Special function quadratic equation name D...

Страница 9: ... REFERENCE DATA E 1 CONVERSION TABLES E 1 E 1 1 Length units E 1 E 1 2 Mass units E 1 E 1 3 Mass flow units E 1 E 1 4 Volume flow units E 2 E 1 5 Volume capacity units E 2 E 1 6 Temperature units E 2 E 1 7 Pressure units E 2 E 1 8 Density units E 3 E 1 9 Dynamic viscosity units E 3 E 1 10 Kinematic viscosity units E 3 E 2 PRODUCT DATA E 4 E 2 1 Density temperature relationship of hydrocarbon produ...

Страница 10: ...7828 Density Transmitter Technical Manual x 78285000_AB ...

Страница 11: ...giving an output proportional to a user selected process parameter or calculation result with configurable span bias limits and filter options line density line temperature API S G base density API base density Solartron matrix method special calculation result 2 An RS485 Modbus interface giving access to other measurement results system information and configuration parameters No signal converter...

Страница 12: ...olids etc 1 1 3 WHAT IS IT USED FOR The 7828 Transmitter is ideally suited to applications where continuous real time measurement of density is required for example in process control where density is the primary control parameter for the end product or is an indicator of some other quality control parameter such as solids or concentration Some examples are Blending Mixing Evaporator control End p...

Страница 13: ...hows and outline of a typical wet process mineral application where 7828 provides a 4 20mA signal of the solids determination from the slurry stream From this signal and the measured volumetric flowrate net mass flowrate is determined The output signal could also be used for solids control or for net mass flow rate ratio blend control The optional RS485 Modbus connection to a PC running ADView can...

Страница 14: ...elloy C22 Electro polished D Hastelloy C22 Hastelloy C22 PTFE laminated G Monel 400 Monel 400 Standard H Monel 400 Monel 400 Electro polished J Monel 400 Monel 400 PTFE laminated L Special Special Special S Sensor electronics Standalone on node 4 20mA BASEEFA EEx d IIC T4 C Process connections 2 ANSI 150RF A 2 ANSI 300RF B 2 ANSI 600RF C 2 ANSI 900RF D 2 ANSI 1200RF E 2 ANSI 1500RF F 50mm DIN 2527...

Страница 15: ...eing unrepresentative of the main flow In some applications absolute accuracy is less important than repeatability For example in a system where the control parameters are initially adjusted for optimum performance and thereafter only checked periodically The term achievable accuracy can be used to describe a measure of the product quality that can be realistically obtained from a process system I...

Страница 16: ...285000_AB This chapter has the following sections Section 2 2 The importance of boundary and viscosity effects Section 2 3 Mechanical details for mounting and installing 7828 Section 2 4 Optimising measurement accuracy and repeatability Section 2 5 Commissioning the system ...

Страница 17: ...is eliminated 2 2 1 BOUNDARY EFFECTS Any insertion device or transducer can only measure the properties of the fluid within the region of fluid to which it is sensitive For practical reasons it is helpful to consider the sensitive or effective region for the transmitter as an three dimensional ellipse centred on the tips of the tines with its long axis aligned with the direction in which the tines...

Страница 18: ... The smaller circle represents a 4 vertical pipe which intersects the effective region The 6 150mm pipe is the smallest pipe diameter to completely enclose the effective region when the pipe is vertical Thus smaller pipe diameters can lead to a variety of different geometries which would each require a separate calibration An alternative condition is shown in the next diagram where the side pocket...

Страница 19: ...t almost every installation requires a separate in situ calibration a very undesirable situation The problem is resolved by providing standard calibration geometries which can be used in all pipe work configurations and thereby allow the factory calibration conditions to be reproduced in the process These standard geometries are described in section 2 3 ...

Страница 20: ...e action to be taken to minimise them is given below Viscosity range Remedy T piece installations only Less than 100cP Greater than 100cP 1 None required Density measurements may be unpredictable use flow through chamber or free stream installation All other installations Up to 500cP None required 500 to 20 000cP steady Perform simple on site calibration to derive density offset adjustment see Cal...

Страница 21: ... s at main pipe wall 10 to 30 l min 2 6 to 8 US gal min Viscosity limits Up to 20 000cP Up to 100cP 250cP in some cases Up to 20 000cP Temperature 50 to 200 C 58 to 392 F 50 to 200 C 58 to 392 F 50 to 200 C 58 to 392 F Main flow pipe size 100mm 4 horizontal 150mm 6 vertical or larger 50mm 2 or larger Any Advantages simple installation in large bore pipes ideal for clean fluids and non waxing oils ...

Страница 22: ...ween the tines vertical This is irrespective of the pipe line orientation and helps to prevent the trapping of bubbles or solids on the transducer Note All drawings and dimensions given in the following sections are derived from detailed dimensional drawings They are given here for planning purposes only Before commencing fabrication reference should always be made to the current issue of the appr...

Страница 23: ...ransducer to temperature changes The view shown below is schematic to show the dimensions of the side pocket which is fabricated by the end user The pocket can be fabricated with 2 schedule 40 80 or 160 tube without affecting the calibration Counter bore the pocket to a minimum depth of 13mm and diameter 52 6 0 1mm to locate the 7828 centrally Weld neck or slip on flanges may be used according to ...

Страница 24: ... that the tines of the 7828 are orientated correctly and are fully inserted into the fluid stream Before fitting the weldolet the pipeline must be bored through at 52 5mm diameter to accept the viscometer The weldolet must be welded to the pipeline concentrically with the pre bored hole The view shown below is schematic to show the relevant dimensions 52 5mm min 254mm Horizontal 4 or larger Vertic...

Страница 25: ...he dimensions of the side pocket which is fabricated by the end user The pocket geometry must be consistent with 2 schedule 40 tube in both internal diameter and minimum wall thickness i e internal diameter 52 5mm minimum wall thickness 3 192mm Alternatively schedule 80 or 160 tube may be used but this affects the calibration and must therefore be specified when ordering the sensor Counter bore th...

Страница 26: ... by the flow rate in the main pipeline refer to the table in the diagram below and is chosen to ensure that the tines of the 7828 are sufficiently retracted from the main pipe wall Dimension X should be the smallest possible consistent with the maximum expected flow rate Before fitting the weldolet the pipeline must be bored through at 52 5mm diameter to accept the viscometer The weldolet must be ...

Страница 27: ...00 C Pressure 70 bar at 204 C subject to process connections The PT100 is a direct insertion type without a thermowell and uses a Swagelok connection The diagram below shows the dimensions of this type of standard installation A B Drain 1 Swagelok fittings Flow in Flow out Note Datum lines must be preserved when fitting flanges to weld prepared tubes 238mm 1 tubes or 246mm 2 tubes Dims in mm A B 1...

Страница 28: ...ns such as Condition of fluid at the sensor Thermal effects Flow rate Entrained gas Solids contamination 2 4 1 FLUID AT THE SENSOR The fluid in the effective zone of the 7828 must be of uniform composition and at uniform temperature It must be representative of the fluid flow as a whole This is achieved either by mixing of the fluid either using a static inline mixer or taking advantage of any nat...

Страница 29: ...as entrainment must be avoided This can be achieved by observing the following conditions Keep pipe lines fully flooded at all times Vent any gas prior to the density transmitter Avoid sudden pressure drops or temperature changes which may cause dissolved gases to break out of the fluid Maintain a back pressure on the system sufficient to prevent gas break out e g back pressure equivalent to twice...

Страница 30: ...ers or sample take off for by pass installed sensors Heat Loss Heat Loss Higher temperature Lower density Lower temperature Higher density Density 2 5 COMMISSIONING 1 Once the pipework installation has been prepared and before installing the 7828 fit a blanking flange or compression nut to the 7828 mounting and pressurise and flush the system 2 Isolate the system depressurise and remove the blanki...

Страница 31: ...ugh you may not immediately require the Modbus connection it may be required for in situ calibration adjustment and future system enhancements and the cost of the additional wires is trivial compared to the expense of installing them retrospectively A number of factors must be taken into account when planning the electrical installation These include Power supply Section 3 2 1 EMC Section 3 2 2 Gr...

Страница 32: ...ded that the transmitter be connected using a suitable instrumentation cable containing an overall screen This should be earthed at both ends of the cable At the transmitter the screen can be earthed to the transmitter body and therefore to the pipework using a conductive cable gland 3 2 3 GROUND CONNECTIONS It is not necessary to earth the transmitter through a separate connection this is usually...

Страница 33: ... are supplied with the 7828 but you may need alternatives to meet local electrical installation regulations In hazardous areas these items must be explosion proof 3 2 5 SURGE PROTECTION Careful consideration should be given to the likelihood of power supply surges or lightning strikes The power supply connections within the 7828 have a surge arrestor fitted to offer protection against power supply...

Страница 34: ...4 3 5 6 Notes Always conform to local codes of practice and regulations The main 24V power supply must supply between 20 and 28V dc at 70mA The RS485 232 converter and PC are not normally installed permanently However it is strongly recommended that the wiring to the 7828 is made at installation The 4 20mA analog output is not self powered an external supply is required The main power supply can b...

Страница 35: ...7828 GRUB SCREW UNDO THIS CAP 2 With the 7828 mounted horizontally to ensure that the slot in the tines is vertical the NPT holes will be in a vertical plane The cable entry should be at the lowest point to help minimise water ingress NPT hole NPT hole 3 Fit the M20 gland adaptor into the lowest hole then fit the M20 x 1 cable gland to the adapter Fit the NPT blanking plug to the unused hole in th...

Страница 36: ...rminal blocks 5 Wire up the cable cores as shown Power Power 4 20mA 4 20mA RS485 A RS485 B 1 2 3 4 5 6 6 5 4 3 2 1 6 When you have screwed the wires into the correct terminals carefully tuck the wires around the electronics and tighten the cable gland 7 Finally screw the housing cap on fully and tighten the locking grub screw using the 2 5mm AF hex drive TIGHTEN CAP TIGHTEN HEX GRUB SCREW VIEW FRO...

Страница 37: ...e familiar RS232 standard which utilises the voltage between the signal core and a common earth A brief summary of some typical characteristics of the two standards is given below RS485 RS232 Signal detection Differential Single ended Receiver threshold 200mV 1 5V Transmitter output swing 0 to 5V no load 2 to 3V 120 ohm load 8V A converter is required for communication between the two standards Fu...

Страница 38: ... the K485 ADE converter manufactured by KK Systems Ltd and obtainable from Solartron part number 550003520 this will work with Windows 3 1 95 98 and NT The converter s RS485 connection is a 9 way plug and the RS232 connector is a 25 way socket which may require an adaptor to plug into the PC s RS232 port commonly a 9 way plug Solartron s ADView software part number 7828 1A includes ADView software...

Страница 39: ...485 ADE is three way isolated providing isolation between the two ports and the power supply It requires a 7 to 35V power supply and typically takes 1 to 2W power consumption is largely independent of supply voltage It is capable of working with Windows 3 1 95 98 and NT The default configuration of the KD485 ADE has Port 2 configured for 9600 baud Further details of this device including configura...

Страница 40: ...D RxA TxA TxB Note For a PC running Windows NT the RTS connection can be omitted Connections to the RS485 port Port 2 are KD485 ADE Tx Rx RTS In Port 1 GND Power Input 1 2 3 4 5 6 7 8 6 5 4 3 2 1 Port 2 RS485 RxB Port 2 GND RxA TxA TxB A B A B GND GND 3 4 2 7828 A B GND 3 4 2 7828 Note The A signals on the 7828 must be connected to the B signal on the converter and vice versa In most systems the g...

Страница 41: ...l to B 3 4 5 TRANSMISSION MODE The 7828 RS485 interface uses the following parameter settings which are not selectable Baud rate 9600 Bits 8 Parity None Stop bits 2 3 4 6 ANALOG 4 20MA OUTPUT The 4 20mA output of the 7828 can be configured to be proportional to a user defined range of either density base or referred density temperature or one of the special functions Fault conditions within the 78...

Страница 42: ...vice and therefore the connections shown in the wiring schedule are applicable However it is essential to observe the rules of compliance with Current Standards concerning flameproof equipment 1 The electronic housing covers should be tightened securely and locked in position by their locking screws 2 The electrical cable or conduit should have an appropriate explosion proof cable gland fitted 3 I...

Страница 43: ...itter Displaying data in real time or as a graph Logging data to a file Verifying correct operation of the system and diagnosing faults Loading or storing Modbus register values Read write to individual Modbus registers 4 2 INSTALLING ADVIEW Identify the three floppy disks containing the installation files for ADView Insert Disk 1 into an appropriate drive on your PC Run setup exe Open File Manage...

Страница 44: ...density transmitter such as the 7835 or 7828 to gain some experience with the software To run the simulation choose Options Simulate board response from the menu bar and choose the Fork densitometer option When this is chosen ADView ignores the serial port and supplies simulated data 4 3 1 SETTING UP SERIAL COMMUNICATIONS To operate with a real Modbus device you will need to connect it to a suitab...

Страница 45: ... determine whether the operating system is Windows NT If it is ADView does not toggle RTS and you will need to use an RS232 485 adapter which automatically switches the data direction without using RTS To set the OS variable click on the Start button then choose Settings Control Panel Click on the System icon and select the Environment tab A list of environment variables and their values is shown ...

Страница 46: ...285000_AB If no active device is found a warning message is given In this case check that the device is powered up correctly that the cables and adapter are pushed fully home and that the communications settings on the device and selected serial port are the same ...

Страница 47: ...parameter and the analog output Data logging See section Error Reference source not found Provides tabular data from transmitters of line and base density temperature and special function One parameter can be displayed as a graph Data can also be logged to a file in either Excel tab delimited or Notepad space delimited formats The frequency at which results are logged can be set and logging can be...

Страница 48: ...es as configured by the Windows system settings Window Provides a means of opening or selecting ADView s facilities Help Help on ADView Limited help text best read when first using ADView About ADView Displays software version number 4 4 3 CONFIGURING A SLAVE ADDRESS The 7828 factory configuration sets the slave address to 1 However in many applications it will be necessary to allocate another add...

Страница 49: ...be required to fine tune the calibration of the transmitter see Section 5 However ADView does have tools for reading and writing to individual Modbus registers using the Tools Register Read Write facility and for direct communication on the Modbus using Tools Direct Comms More details and examples are given in Appendix D but for the significant majority of applications these tools will not be requ...

Страница 50: ...t The calculated parameters special functions available depend on whether Matrix or API referral is selected Select units for variable controlling analog output Enter line pressure value here Select from 1s to 100s or no averaging Select referral type see text for more details Click on Configure to select and configure Special function calculated parameter See text for more details Select any comb...

Страница 51: ... or enter your own values Special Functions The range of special functions calculated parameters that are available depends on the referral type selected Special Function API referral Matrix referral Specific Gravity API mass volume Baumé Brix User defined quadratic None When you select the Special Function you require the configuration window will alter to allow you to input the relevant paramete...

Страница 52: ...er Tabular display of instantaneous output of transmitter Use this button to start logging Use this button to stop logging Use this button to close Data Logging window Use this button to configure and display graph Use this button to select the transmitter and parameter to be displayed on the graph This button which is activated when logging has been stopped enables you to configure the frequency ...

Страница 53: ...or any reason Also if you send the transmitter away for servicing or re calibration you should save the current configuration Details are given below Address of unit being accessed Enter desired filename for Dump or required filename for Load Choose data delimiter Dump only Choose which sets of registers to save to file or simply save all of them You can also specify individual registers Restore a...

Страница 54: ...guard your configuration if anything goes wrong From ADView s menu bar select Tools Register Read Write Click here to see complete list of Modbus register numbers and descriptors Choose the one you want to access For non numerical values click here to see complete list of possible entries and select one to write into the register Enter numerical values directly The current register number appears ...

Страница 55: ...TANDARDS The Transfer Standard instruments used in the calibration are selected instruments which are calibrated by the British Calibration Service Calibration Laboratory and are certified Transfer Standard calibration uses a number of density certified liquids one of which is water The densities of these reference liquids are obtained using the Primary Measurement System whereby glass sinkers of ...

Страница 56: ...ients When the 7828 is calibrated in a known environment K0 K1 and K2 are selected to optimise the density measurement across the calibrated density range As you can also see in the sample calibration certificate temperature effects are also compensated for using a second equation ρ ρ 1 K18 t 20 K19 t 20 where ρ is the new temperature compensated density value t is the measurement temperature and ...

Страница 57: ...7828 Density Transmitter Technical Manual Calibration check 78285000_AA 5 3 5 2 SAMPLE CALIBRATION CERTIFICATE Note This is an example only it is NOT the calibration certificate for your 7828 ...

Страница 58: ...ferent from the fluid used for the factory calibration In practice this affects the density measurement by less than 1 kg m 3 d If the unit has suffered long term drift or corrosion of the tines The 7828 is a very accurate and stable instrument and will normally provide good measurements If it is suspected of giving incorrect results you should confirm this by carefully checking the integrity of t...

Страница 59: ...tem has reached its stable operating temperature 3 When equilibrium conditions of product flow are reached note the 7828 density reading and temperature and simultaneously isolate the pyknometer from the sample flow 4 Remove the pyknometer for weighing to establish the product density 5 Compare the pyknometer reading with the 7828 reading and compute the density offset required 6 Using ADView s Re...

Страница 60: ...Calibration check 7828 Density Transmitter Technical Manual 5 6 78285000_AA ...

Страница 61: ...r performance If a fault or a drop in performance is detected further tests are required to identify the cause of the fault Remedial action is limited to cleaning the transducer tines making good any poor connections and replacing the internal electronics In the extreme cases the complete transducer may need to be replaced Note The electronics within the 7828 contain calibration information releva...

Страница 62: ...n DO NOT FAIL to tighten the locking screws 6 2 2 ELECTRICAL CHECK Check the power supply and current consumption at the transmitter terminals pins 1 and 2 These should give 35mA to 42mA at 22 8V to 25 2V If the current consumption outside this range contact Solartron 6 2 3 CALIBRATION CHECK a Carry out a check calibration as detailed in Section 5 b Compare the results obtained with the previous c...

Страница 63: ... formation of bubbles remove cause of vibration Alternatively it may be necessary to adjust the Time Period Trap see section 6 3 2 Readings outside limits Deposition and or corrosion on the tines Clean tines see section 6 3 1 Analog output 0mA No power to analog output Analog output circuit failure If voltage across pins 5 and 6 is not 15 to 28V replace power supply Use ADView s facility to set th...

Страница 64: ... of a fine abrasive will usually be sufficient However where extensive corrosion has been treated it is highly recommended that a full calibration is carried out to check the transmitter characteristics CAUTION Care is essential in handling the transducer during transit installation and removal from the pipeline tank 6 3 2 TIME PERIOD TRAP Disturbances in the fluid caused by bubbles cavitation or ...

Страница 65: ...that the transient has passed or b the TPT count is reached At this point it is assumed that the change in value is not due to a random disturbance and the output adopts the value of the latest reading Two Modbus Registers control the operation of the Time Period Trap facility These can be changed if necessary using ADView s Register Read Write facility see section 4 Modbus Register 138 contains t...

Страница 66: ...Maintenance 7828 Density Transmitter Technical Manual 6 6 78285000_AA ...

Страница 67: ...le which utilises the Modbus protocol to provide a means of configuring the device retrieving data measurements and performing diagnostics ADView a PC software application running under Windows 3 1 95 98 or NT is available for data logging configuration and diagnostics purposes A 2 SPECIFICATION A 2 1 SENSOR PERFORMANCE Density measurement Measurement technology Tuning Fork driven sensed by piezoe...

Страница 68: ...ting pressure 207 bar 3000psi Enclosure Type Die cast low copper alloy Polyurethane paint finish Protection IP66 Max weight 6 7 kg Max vibration 0 5g continuous A 2 3 TRANSMITTER POWER SUPPLY Minimum Input Voltage 20V Maximum Input Voltage 28V Current Consumption 35 to 45mA A 2 4 ANALOG OUTPUT Number of channels 1 Range 3 9mA to 20 8mA Alarm Condition 2mA Nominal Power Supply 24V Maximum Terminal ...

Страница 69: ...nections A and B signals screw terminals Communications protocal Modbus RTU Isolation None RS485 in same circuit as main power supply Baud rate 9600 fixed Termination not required A 2 6 APPROVALS EMC EN50081 2 1994 EN50082 2 1995 Approvals EEx d IIC T4 BASEEFA CSA Class 1 Division 1 Group C pending ...

Страница 70: ...pecification All other default settings are as for Option A The default values for these three configurations are shown below Options A and C Option B Analog output Variable Line density Base density API Units kg m 3 g cc 4mA setting 500 0 5 20mA setting 1500 1 5 Alarms Coverage General system Analog output User range General system Analog output User range Hysteresis 2 2 Alarm user range Variable...

Страница 71: ...ial Functions Type None None Name 0 None 0 None Units None None Density of water d 998 0 998 Density of Product A 0 0 Density of Product B 0 0 Quadratic coefficients A B C 0 0 Output averaging time 1s 1s Modbus Slave address 1 1 Byte order Big Endian Big Endian Register size 16 bit 16 bit Hardware type Advanced fork Advanced fork For Option C the Matrix referral constants will have been configured...

Страница 72: ...Specification 7828 Density Transmitter Technical Manual A 6 78285000_AB ...

Страница 73: ...lculated parameter is available at any one time it can be used to control the analog 4 20mA output and can also be accessed as a digital value Modbus Register 260 This section describes the algorithms used in these calculations The availability of the calculated parameters is dependent on whether Matrix or API is chosen as the density referral method Special Function API referral Matrix referral S...

Страница 74: ...Line Temperature measured Line Density ρ measured Base Referred Density ρB calculated The lines D1 to D4 plot the density of four product types for which the density is known at five different reference temperatures T1 to T5 Using this information and the measured line density and temperature the 7828 calculates the base density at the base temperature The information required for the referral is ...

Страница 75: ...d Density Temperature Relationship Correction factors in the revised API ASTM IP petroleum measurement tables are based on the following correlation equations ρt ρ15 exp α15 t 1 0 8 α15 t where ρt Density at line temperature t C ρ15 Density at base temperature 15 C t t 15 C α15 Tangent thermal expansion coefficient per deg C at base temperature of 15 C The tangent coefficient differs for each of t...

Страница 76: ... K1 Crude oil 613 972226 0 0000 User defined factors can be entered as any sensible value Density Pressure Relationship Isothermal secant compressibility can be defined by the simplified equation β δ 1 0 1 1 V V P t where liquid volume changes from V0 to V1 as the gauge pressure changes from zero atmospheric to P1 where β Isothermal secant compressibility at temperature t δV1 Change of volume from...

Страница 77: ...285000_AA B 5 A correlation equation has been established for β from the available compressibility data i e loge C 1 62080 0 00021592t 0 87096 x 10 6 ρ15 2 4 2092t x 10 3 ρ15 2 per bar where β C x 10 4 Bar t Temperature in deg C ρ ρ15 1000 oil density at 15 C kg litre ...

Страница 78: ...ferral is selected Degrees Baumé 145 145 Base density where Base density is measured in g cc B 3 3 DEGREES BRIX Only available when Matrix referral is selected Degrees Brix 318 906 384 341 SG SG2 661086 where SG is Specific gravity B 3 4 QUADRATIC EQUATION Only available when Matrix referral is selected The following quadratic equation is implemented y A B d C d B B ρ ρ 2 where A B C are User prog...

Страница 79: ... A K2 base density of product B ρB base density of mixture B 3 6 VOLUME Only available when Matrix referral is selected volume of product A ρB K K K 2 1 2 100 where K1 base density of product A K2 base density of product B ρB base density of mixture B 3 7 API DEGREES Only available when API referral is selected API SG 1415 1315 The base density used for specific gravity value is determined from AP...

Страница 80: ...Calculated parameters 7828 Density Transmitter Technical Manual B 8 78285000_AA ...

Страница 81: ...A 2 Addition of 7827 Viscometer C of C Variation Ex 91C1359 2 22 Oct 93 BASEEFA 2 Addition of PTFE coating variants other minor amendments C of C Variation Ex 91C1359 3 31 Aug 94 BASEEFA 2 Alternative potting materials C of C Variation Ex 91C1359 4 28 Nov 94 BASEEFA 2 Minor amendments C of C Variation Ex 91C1359 5 22 Dec 95 BASEEFA 2 Minor amendments to terminal board C of C Supplement Ex 91C1359 ...

Страница 82: ...7828 Density Transmitter Technical Manual Safety Certification C 2 78285000_AC ...

Страница 83: ...and only communicates on the network when it receives a request for information from a Master device such as a computer or a PLC The implementation used on the 7828 is fully compliant with the Modicon Specification All information is stored in memory locations in the 7828 referred to as Modbus Registers These store all the data required to control the operation calculations and data output of the ...

Страница 84: ...t Communications This is another tool which allows you to compose a sequence of data to be transmitted to from the Modbus This can be used to communicate with any Modbus device providing that you know the register addresses data format indices etc The composition of the data is entirely up to the user although the tool does compute and insert a checksum Only those well versed in the use of Modbus ...

Страница 85: ... to suit the communicating device if it cannot easily be re programmed This is most easily done using ADView s Register Read Write tool see Section 4 Their usage is as follows Modbus Byte Ordering Register 47 contents Modbus Byte Ordering 0000000016 Big Endian i e MSB first FFFFFFFF16 Little Endian i e LSB first Modbus Register Size Register 48 contents Modbus Register size 0000000016 16 bits FFFF...

Страница 86: ... in section D 5 Register Function Data Type Index Table where applicable 0 API product type Long integer D 5 1 1 API referral reference temperature 4 byte float 2 API referral reference pressure 4 byte float 3 Line density units Long integer D 5 2 4 Base density units Long integer D 5 2 5 Temperature units Long integer D 5 2 6 Special function calculation type Long integer D 5 3 7 Special function...

Страница 87: ...nteger 138 Transducer time period trap difference in µs 4 byte float 139 Time period value when fixed by diagnostics 4 byte float 140 Value represented by 4mA on analog output 4 byte float 141 Value represented by 20mA on analog output 4 byte float 146 Line pressure 4 byte float 147 151 Temperatures for matrix referral 4 byte float 152 171 Densities for matrix referral 4 byte float 172 Atmospheric...

Страница 88: ...t type Long integer D 5 14 256 Status Register Long integer D 5 15 257 Corrected line density 4 byte float 258 Corrected base density 4 byte float 259 Line temperature 4 byte float 260 Special function calculation result 4 byte float 261 Transducer time period in µs 4 byte float 262 FRAM calculated checksums Long integer 263 PRT resistance in ohms 4 byte float 264 Transducer coil pickup level in v...

Страница 89: ... API PRODUCT TYPE Used in Register 0 The user values for K0 and K1 are stored in Registers 182 and 183 Index Product Type 0 Crude general crude 1 Refined general product 2 User K0 and K1 D 5 2 PRESSURE TEMPERATURE DENSITY AND OTHER UNITS Used in Registers 3 4 5 and 26 Index Units 6 psi A 7 bar A 10 kg cm 11 Pa 12 kPa 32 C 33 F 57 90 SGU 91 g cm 92 kg m 93 lb gal 94 lb ft 101 Brix 102 Baume heavy 1...

Страница 90: ...lume 3 Specific Gravity 4 Baume 5 Brix 6 General Quadratic Equation 7 API D 5 4 SPECIAL FUNCTION QUADRATIC EQUATION NAME Used in Register 7 Index Name 0 none 1 Density 2 Mass 3 Volume 4 Baume 5 Brix 6 Specific Gravity 7 Gravity 8 API 9 Plato 10 Twaddle 11 Alcohol 12 reserved 13 reserved 14 reserved 15 reserved 16 reserved 17 reserved 18 reserved 19 reserved ...

Страница 91: ...ON UNITS Used in Register 8 Index Name 0 none 57 D 5 6 OUTPUT AVERAGING TIME Used in Register 9 Index Averaging Time 0 none 1 1 s 2 2 s 3 5 s 4 10 s 5 20 s 6 50 s 7 100 s D 5 7 ANALOGUE OUTPUT SELECTION Used in Register 10 Index Output 0 Density 1 Referred Density 2 Temperature 3 Special Function 4 4 mA 5 12 mA 6 20 mA ...

Страница 92: ... matrix 1 2 3 4 Highest temperature value in matrix D 5 9 ALARM COVERAGE Used in Register 29 Bit Pattern Coverage 0x00000001 4 20 mA output 1 alarm 0x00000008 System error 0x00000010 User defined alarm D 5 10 ALARM HYSTERESIS Used in Register 31 Index 4 20 mA Output Hysteresis 0 0 1 0 5 2 1 3 2 4 5 5 10 D 5 11 SOFTWARE VERSION Used in Register 49 Index Density Referral 0 Matrix 1 API ...

Страница 93: ... Registers 61 Index Meter Type 1 Advanced Fork D 5 13 USER SELECTED ALARM VARIABLE User in Register 184 Index Variable 0 Line density 1 Base density 2 Temperature 3 Time Period 4 PRT resistance 5 Special Function 6 Pickup level 7 None D 5 14 UNIT TYPE Used on Register 204 Index Transmitter type 5 Advanced fork ...

Страница 94: ...FT3_HART HART is in control of its 4 to 20 mA output 13 00002000 ST_BAD_STATUS STATUS register corruption 14 00004000 ST_STAT_CORR one or more STATus registers have been CORRected 15 00008000 ST_TOTAL_DEATH status registers not updating assume the worst 16 00010000 ST_USER_ALM User defined variable in alarm 17 00020000 18 00040000 19 00080000 20 00100000 21 00200000 ST_TEMP_HI TEMPerature reading ...

Страница 95: ...32 bits by reading register 48 c Find the byte order by reading register 47 a Make sure only the transducer is connected to the Modbus Master then send the following message Read Register 47 Slave Address Command Register Address Checksum 00 03 00 4710 00 02 checksum Wait for a response If there is none repeat the same message with the Slave address changed to 1 and await a response Repeat the pro...

Страница 96: ...ster 47 Slave Address Command Register Address Checksum nn 03 00 4710 00 02 checksum where nn is the transducer s slave address The transducer will respond with either Slave Address Command Data Bytes Checksum nn 03 04 4 data bytes checksum or Slave Address Command Data Bytes Checksum nn 03 08 8 data bytes checksum Examine the first four bytes of the data If they are all 00 then the transducer is ...

Страница 97: ...or any others you want to try This has the added advantage that ADView calculates and inserts the checksum value for you D 7 1 EXAMPLE 1 READING LINE DENSITY 16 BIT REGISTER SIZE The 7828 is assumed to have been configured with Register Size 16 bit Register 48 0 and has slave address 1 The following string will read the line density which is held in Register 257 010116 01 03 01 01 00 02 94 37 The ...

Страница 98: ...FFF16 and has slave address 1 The following string will read the line density which is held in Register 257 010116 01 03 01 01 00 01 D4 36 The reply from the 7828 will be the same as for Example 1 Slave address hex Command number 3 Read Register Register address Hi byte Register address Lo byte Number of registers to read Hi byte Number of registers to read Lo byte Checksum Automatically inserted ...

Страница 99: ...b h US GPM US BPH kg s 1 3600 3 6 2 2046 132 28 7936 5 15 848 SG 22 624 SG kg h 0 000277 1 0 001 0 000612 0 03674 2 2046 0 0044 SG 0 0063 SG Tonne h 0 277777 1000 1 0 612384 36 74309 2204 585 4 4033 SG 6 2933 SG lb s 0 4536 1632 92 1 63296 1 60 3600 7 1891 SG 10 267 SG lb m 0 00756 27 215 0 027216 0 016666 1 60 0 1198 SG 0 1712 SG lb h 0 000126 0 4536 0 000453 0 000277 0 016666 1 0 002 SG 0 0029 S...

Страница 100: ... US BPH 2 649791 4 42E 5 0 158987 3 8157 42 0 7 1 24 US BPD 0 110407 1 84E 6 0 006624 0 158987 1 75 0 029166 0 041666 1 E 1 5 VOLUME CAPACITY UNITS in 3 ft 3 m 3 litres gal in 3 1 5 787E 4 1 639E 5 0 01639 4 329E 3 ft 3 1728 1 2 832E 2 28 32 7 4805 US liq m 3 6 1024E 4 0 0353 1 1000 264 2 US liq litres 61 02 0 0353 0 001 1 0 2642 US liq gal 231 0 0 1357 3 785E 3 3 785 1 1 Imperial gallon 1 20095 U...

Страница 101: ... 2 s cm 2 s cS 1 1 1 0E 6 0 00155 0 010765 0 01 mm 2 s 1 1 1 0E 6 0 00155 0 010765 0 01 m 2 s 1000000 1000000 1 1550 10 7649 10000 in 2 s 645 16 645 16 0 000645 1 0 006944 6 4516 ft 2 s 92 8944 2 8944 0 092864 144 1 0 928944 cm 2 s 100 100 0 0001 0 155 1 0765 1 Note The dynamic viscosity η of a Newtonian fluid is given by η τ dv dr where τ shearing stress between two planes parallel with the direc...

Страница 102: ...5 05 780 68 806 27 831 83 857 36 882 85 908 32 933 76 959 18 35 759 06 784 57 810 04 835 48 860 90 886 30 911 67 937 02 962 36 30 763 06 788 44 813 79 839 12 864 44 889 73 915 01 940 28 965 53 25 767 05 792 30 817 54 842 76 867 97 893 16 918 35 943 52 968 89 20 771 03 796 18 821 27 846 38 871 49 896 59 921 68 946 77 971 85 15 556 774 56 799 57 824 59 849 60 874 61 899 62 924 63 949 64 974 65 15 77...

Страница 103: ...0 10 654 85 704 66 754 50 803 71 853 53 903 47 953 41 1003 36 1053 32 5 659 67 709 30 758 97 807 41 857 04 906 92 956 81 1006 72 1056 63 0 664 47 713 92 763 44 811 10 860 55 910 37 960 20 1010 07 1059 93 The above tables are derived from equations which form the basis of the data in the Revised Petroleum Measurement Tables IP 200 ASTM D1250 API 2540 and ISO R91 Addendum 1 The density temperature r...

Страница 104: ...0 100 00 55 121 32 110 142 29 165 162 90 90 112 53 200 135 97 E 2 3 DENSITY OF AMBIENT AIR IN KG M 3 Air Pressure Air Temperature C mb 6 10 14 18 22 26 30 900 1 122 1 105 1 089 1 073 1 057 1 041 1 025 930 1 159 1 142 1 125 1 109 1 092 1 076 1 060 960 1 197 1 179 1 162 1 145 1 128 1 111 1 094 990 1 234 1 216 1 198 1 180 1 163 1 146 1 129 1020 1 271 1 253 1 234 1 216 1 199 1 181 1 163 Taken at a rel...

Страница 105: ...opied and completed whenever a Solartron transducer is to be returned for servicing calibration or repair to Solartron or one of their agents This must be done before the product is shipped The purpose of the form is to inform Solartron of any potentially hazardous chemicals which may be present in the transducer or that may have leaked into the casing ...

Страница 106: ...7828 Density Transmitter Technical Manual COSHH Document F 2 78285000_AA ...

Страница 107: ...spillage 4 4 Any further information which you consider relevant 4 5 Please complete Section 4 5 1 if substances are not toxic or Section 4 5 2 if they are 4 5 1 I hereby confirm that the equipment specified above has not come into contact with any toxic or hazardous substances Signed Name Position For and on behalf of Date 4 5 2 I hereby confirm that the only toxic or hazardous substances that th...

Страница 108: ...7828 Density Transmitter Technical Manual COSHH Document F 4 78285000_AA ...

Страница 109: ......

Страница 110: ...y Bestobell Mobrey GmbH Deutschland tel 0211 99 808 0 Solartron Mobrey Ltd China tel 021 6353 5652 Mobrey sp z o o Polska tel 022 871 7865 Mobrey AB Sverige tel 08 725 01 00 Mobrey SA France tel 01 34 30 28 30 Mobrey SA NV Belgium tel 02 465 3879 Solartron Mobrey USA tel 281 398 7890 The right is reserved to amend details given in this publication without notice 78285000 AB Nov 99 ...

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Solartron Mobrey 7828, Техническое руководство

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